Bending device for the working rolls of a hot-rolling frame

ABSTRACT

A hot-rolling stand including blocks arranged in the stand windows and having hydraulic piston cylinder units provided as bending devices which are able to transfer bending forces via guide elements onto the chocks of the working rolls. For each block a double-acting hydraulic piston cylinder unit is provided whose two ends are connected with the guide elements. The guide elements have guide that engage both sides of the free ends of noses of the working roll chocks so as to permit axial movement of the working rolls.

BACKGROUND OF THE INVENTION

The invention relates to blocks arranged in stand windows of hot rollingstands comprising hydraulic piston cylinder units provided as bendingdevice which can transmit bending forces onto the chocks of the workingrolls via guide elements.

Particularly in the case of cold-rolling stands it has been found to bebeneficial to arrange bending devices for the working rolls in blockswhich are preferably arranged at least partially in the recesses of thestand beams. Difficulties resulted in connection with this configurationbecause it is desired that the bending devices provide positive as wellas negative forces and since, moreover, a relative movability of theworking rolls in the axial direction relative to one another isdemanded. Critical in this connection is also the space requirement ofthe bending devices which limits the possibilities of the support of thesupport rolls.

DE 195 36 042 A1 discloses a guide device for four-high and multi-highcold-rolling stands which get by with one bending cylinder on each sideof the chocks. An axial movement of the rolls is ensured in that thebending blocks are arranged moveably in axial guides fixedly connectedto the stand window. These guides cause the stand windows to be greatlyconstricted.

A transfer of the solutions found in connection with cold-rolling standsonto hot-rolling trains is practically impossible because the maximumforces to be developed here surpass those required for cold rolling by afactor of 3. In particular, it was found that at the operating pressurein question, the forces to be applied can no longer be developed by asingle hydraulic piston cylinder unit of an acceptable size,respectively; in the case of hot-rolling stands the blocks comprisingbending devices have therefore been provided with a complexconfiguration and with a number of, for example, 6 up to 12 paralleloperating piston cylinder units, i.e., up to 24 piston cylinder unitsper stand. Moreover, it was found to be disturbing that the bendingdevices had such large dimensions that a free design of the support ofthe support rolls is no longer possible and, for example, Morgoilbearings can no longer be used and rolling bearings have to be employed.

SUMMARY OF THE INVENTION

The invention is thus based on the object to provide working rollbending devices of the aforementioned kind which are capable ofeffecting the advancing forces to be applied by means of a single pistoncylinder unit and whose dimensions are so small that a simplearrangement within the blocks to be provided in the stand window is madepossible and the free selection of the bearings of the support rollsremains ensured.

This object is solved by a hot-rolling stand comprising blocks arrangedin the stand windows, which blocks comprise hydraulic piston cylinderunits provided as bending devices which are able to transfer bendingforces via guide elements onto the chocks of the working rolls. For eachblock a double-acting hydraulic piston cylinder unit is provided whosetwo ends are connected with the guide elements. The guide elements haveguide grooves that engage both sides of the free ends of noses of theworking roll chocks to thereby allow an axial movement of the workingrolls. These features make possible the configuration of bending deviceswhich constrict the stand window only moderately and therefore providesufficient space for the chocks of the support rolls as well as theirbearings.

In detail, the features of the invention are explained with the aid ofthe description of one embodiment in connection with the drawingillustrating it.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a section through a bending device pursuant to the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

In the FIGURE a beam 1 of a frame of a hot-rolling stand is illustratedin a detail view and is provided with a bending device illustrated invertical section. The important components of this bending device 2 arearranged in a hollow-cylindrical housing 3. A vertically movablepressure cylinder 4 contains in its upper widened area, which is guidedwithin the housing 3, a piston 5 whose piston rod 6 is guided in thelower area of the pressure cylinder 4, which has a reduced outerdiameter, within a plunger sleeve 7. The sleeve, in turn, is guided bythe wear surfaces 8 of the housing 3. The piston rod 6 penetrates aflange of the plunger sleeve 7 and is supported thereon by means of apressure ring 9 while the end bushing 11, secured by an end plate 10, isable to transmit tensile forces of the piston rod 6. The end plate 10 isprovided with a lateral nose which engages a cutout of the plungersleeve 7 which nose, together with a bolt connected thereto, serves as arotary securing means for the piston 5 and the piston rod 6.

A guide element 12, 13 is connected to the end face of the pressurecylinder 4 as well as the lower front of the plunger sleeve 7,respectively, and supported rearwardly in the stand window by andaligned with vertical wear plates 14, 15.

The working rolls 16, 17 of the hot-rolling stand, embodied as afour-high stand, are supported with bearings, not illustrated, in thechocks 18, 19. These chocks have laterally projecting noses 20, 21 whichengage grooves 22, 23 of the guide elements 12, 13 and are supported bymeans of pressure plates 24 against their flanks to thereby allow anaxial movement of the working rolls. The nose 21 is provided with afurther pressure plate on which the complete working roll set can bemoved for exchanging them.

In operation the following function results: The nose 20 of the chock 18secures the guide piece 12 by means of the pressure plates 24 supportedon the flanks of the groove 22 at a height correlated with the workingroll 16, while the position of the working roll 17 determines by thenose 21 and its pressure plates 24 supported on the flanks of the groove23 the height of the guide element 13. The plunger sleeve 7 and thepiston rod 6 of the piston 5 are connected with the guide element 13,while the guide element 12 is screwed onto the pressure cylinder 4. Thismeans that the position of the chocks 18 and 19 also determines theposition of the piston 5 in the pressure cylinder 4. Corresponding tothe applied control, the upper and/or the lower cylinder chamber formedwithin the pressure cylinder 4 is now pressurized and thus the surfacesof the double-acting piston 5 are correspondingly loaded. The forceswhich are thus developed on the piston surfaces are then transmitted tothe guide elements 12, 13 which are vertically moveable by means of theguide surfaces of the pressure cylinder 4 and of plunger sleeve 7 in thehousing 3 and load via the noses 20, 21 the chocks 18, 19 with therequired pre-stress.

For exchanging the rolls, the working rolls 16, 17 are lifted by thelifting rail 28 wherein the lower chock 19 is supported with itspressure plate 25 provided on the nose 21 on the lifting rail 28.

For the exchange of rolls it is expedient and known to secure the partsof the bending device in the position predetermined for the exchange ofrolls in order to be able to return them without further adjustmentafter extending the roll. In the illustrated embodiment a hydrauliccylinder 29 is provided here in a cutout of the beam 1 whose piston 30is provided with a centering bolt 31. In the drawing this bolt isillustrated in the arrested position in which the piston 30 is extendedand the bolt 31 has been inserted into a recess of the guide piece 12,thereby holding it at a constant height.

OVERVIEW OF REFERENCE NUMERALS

-   1. beam-   2. bending device-   3. housing-   4. pressure cylinder-   5. piston-   6. piston rod-   7. plunger sleeve-   8. wear surface-   9. pressure ring-   10. end plate-   11. end bushing-   12. guide element-   13. guide element-   14. wear plates-   15. wear plates-   16. working roll-   17. working roll-   18. chock-   19. chock-   20. nose-   21. nose-   22. groove-   23. groove-   24. pressure plate-   25. pressure plate-   26. chock-   27. lower support roll-   28. lifting rail-   29. hydraulic cylinder-   30. piston-   31. bolt

1. Hot-rolling stand comprising blocks arranged in the stand windowscomprising hydraulic piston cylinder units provided as bending deviceswhich are able to transfer bending forces via guide elements onto thechocks of the working rolls, wherein for each block a singledouble-acting hydraulic piston cylinder unit (4, 5) is provided whosetwo ends are connected with the guide elements (12, 13), and wherein theguide elements (12, 13) have guide grooves (22, 23) that engage bothsides of the free ends of noses (20, 21) of the working roll chocks (18,19) so as to permit axial movement of the working rolls (16, 17),wherein the block is formed as a housing (3) which is provided withsupport surfaces for wear strips of the working roll chocks (18, 19),and wherein the pressure cylinder (4) of the piston cylinder unit aswell as a transmission element (plunger sleeve 7) engaging the pistonrod (6) are arranged vertically slidably in the interior of the housing(3).
 2. Blocks arranged in the stand windows of hot-rolling standsaccording to claim 1, wherein one of the guide elements (12) isconnected with the pressure cylinder (4) and the second guide element(13) with the transmission element (plunger sleeve 7).
 3. Blocksarranged in the stand windows of hot-rolling stands according to claim1, wherein the guide elements (12, 13) with their sides facing away fromthe noses (20, 21) of the chocks (18, 19) are supported on vertical wearplates (14, 15) connected to the stand.
 4. Blocks arranged in the standwindows of hot-rolling stands according to claim 1, wherein the upperguide element (12) has correlated therewith an adjusting device whichcomprises a bolt (31) insertable into a recess of the guide element(12).